University of Wyoming College of Engineering Professor John Pierre, right, points out the location of major electric transmission lines to M.S. degree candidate Ashish Subramanian of India and Ph.D. candidate Frank Tuffner of Sheridan. The UW team is conducting tests to help prevent large-scale power outages in the western United States.
(UW Photo)

UW Research Helps Reduce Large-Scale Power Outages

April 3, 2006 - In the 2001 National Energy Policy Report, President Bush directed the secretary of energy to expand the Department of Energy's research and development on power grid transmission reliability. Professor John Pierre and his graduate students in the Department of Electrical and Computer Engineering have received grants totaling more than $500,000 to assist in developing a system to monitor power grids.

The entire western United States and parts of Canada form one large power grid, and Pierre says a major event in one part of the West can affect the entire region. With modern electronics, the power utilities are able to collect an immense amount of measured information about the flow of electricity throughout the power grid. Advanced communication systems are used to relay all this information from all over the grid simultaneously back to control centers.

“The challenge our project faces is how to take all this measured information and make complex calculations to find out how close the grid is to instability, a condition that would cause a blackout,” Pierre says. “Frequently, these outages occur in the late summer when the power grid is heavily stressed from the large consumption of electricity.”

Wyoming is a major exporter of electricity. Pierre points out that the state is looking at the possibility of generating and delivering more electricity through new transmission lines, so it is important to understand how that will affect the power grid’s stability.

“The better we understand the transmission grid, the more electricity we will be able to transmit over existing and new transmission lines,” he says.

The researchers have been looking at dynamic stability. When there is a sudden change to the power grid, such as a line tripping out, the electric power flowing on the transmission line oscillates up and down.

“The power grid can't tolerate sustained oscillations in the power flow, and worse yet are oscillations that grow larger,” he says. “That is exactly what happened in the August 1996 outage in the western United States when the oscillations grew so large that blackouts resulted.”

There are many aspects to the project at UW, ranging from analyzing measurements under normal operating conditions to injecting test signals into the power grid. Pierre and his graduate students were part of a major test of the western area power grid carried out by BPA last September, using signals designed at UW. He says these tests were “very successful in providing information about the stability condition of the grid.”

Pierre says the research being conducted at UW should help fulfill the Department of Energy's 2002 National Transmission Grid study, which called for real-time monitoring of the power system to permit the introduction of sophisticated automatic controls to prevent blackouts. In the future, Pierre says he would like to see the techniques they have developed implemented in real-time at control centers.

Pierre joined the UW College of Engineering in 1992. He received his B.S. degree (1986) at Montana State University, and earned M.S. (1992) and Ph.D. (1991) degrees at the University of Minnesota.

Current and former graduate students involved in the project are Mike Anderson, Irene Legowski, Ashish Subramanian, Frank Tuffner, Rich Wies, and Ning Zhou.